First off do you have an owners manual? If so there may be some information about winterizing and dewinterizing. If not try and find a manual.
This is going to be all but a guess. First off try and find your "low point drains" there should be at least two one for the hot line and one for cold. Open them up along with a faucet to drain that is in the line.
Does your water pump have a may be two foot capped plastic hose comeing off of it? If so that is used to suck up the rv antifreeze. There is a valve that will shut that action off causing the pump to pump water from holding tank. You did not say if you were or could get water from direct source.
You also will have to find the water heater "bypass valves" you may have one, two or three it just depends.
If possible you could also take it to a dealer or have a mobile tech come and show you how to dewinterize.
Good Luck
Itasca Meridian SE 36g
Road Master Tow Dolly